1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a communication method supporting heterogeneous systems.
2. Related Art
The institute of electrical and electronics engineers (IEEE) 802.16e standard was adopted in 2007 as a sixth standard for international mobile telecommunication (IMT)-2000 in the name of ‘WMAN-OFDMA TDD’ by the ITU-radio communication sector (ITU-R) which is one of sectors of the international telecommunication union (ITU). An IMT-advanced system has been prepared by the ITU-R as a next generation (i.e., 4th generation) mobile communication standard following the IMT-2000. It was determined by the IEEE 802.16 working group (WG) to conduct the 802.16m project for the purpose of creating an amendment standard of the existing IEEE 802.16e as a standard for the IMT-advanced system. As can be seen in the purpose above, the 802.16m standard has two aspects, that is, continuity from the past (i.e., the amendment of the existing 802.16e standard) and continuity to the future (i.e., the standard for the next generation IMT-advanced system). Therefore, the 802.16m standard needs to satisfy all requirements for the IMT-advanced system while maintaining compatibility with a mobile WiMAX system based on the 802.16e standard.
The IEEE 802.16m standard requires to guarantee coexistence of heterogeneous systems such as an IEEE 802.16e system, a time division synchronous code division multiple access (TD-SCDMA) system, and a long term evolution (LTE) system. There is a need to decrease interference between a system based on the IEEE 802.16m standard and the heterogeneous systems.